This invention claims priority to German Utility Model Application 201 19 000.1, filed on Nov. 21, 2001, which is incorporated herein by reference in its entirety.
The present invention relates to a cylindrical covering cap for eyepiece tubes, having a conical soft eyecup, the inner aperture radius R1 of the covering cap being adapted to the larger outside radius RK of the cone of the eyecup.
Covering caps of this type are generally known. They usually consist of plastic and are pushed onto the eyepiece tube. Given a suitable pressure, they are clamped onto the cone of the eyecup (with the aid of the coating, which is soft like rubber) so firmly as to prevent it from falling off inadvertently. However, clamping frequently occurs that is so firm that the covering cap may be detached only by a forceful tug. In this process, the soft coating of the eyecup can also be taken off. In an attempt to detach the covering cap by rotation, rotatable eyecups for eyepieces for spectacle wearers are partially rotated out of their end click stops and detached from the eyepiece tube. It is also disadvantageous that on being gripped during detachment the covering cap is initially pressed even more firmly onto the eyecup.
An object of the present invention is to solve these and other problems by specifying a covering cap which, on the one hand, is securely seated on the eyepiece tube simply by being pushed on and, on the other hand, can be detached without damaging the eyecup.
The present invention provides for a cylindrical covering cap for an eyepiece tube, the eyepiece tube having a conical soft eyecup, which comprises, in a cylindrical interior of the covering cap: two mutually opposite segment regions having a segment region inside radius R2 that is greater than an inner aperture radius R1 of the covering cap; and at least two mutually opposite segment surfaces, wherein a shortest distance A from a segment surface to a cylinder axis passing through a center of the covering cap is smaller than the inner aperture radius of the covering cap, and wherein the inner aperture radius R1 of the covering cap is configured to adapt to a larger outside radius RK of the conical eyecup. The segment surfaces may be circumferentially spaced so that the locations of the segment surfaces are approximately symmetric about a segment region axis that passes through a center of each of the segment regions. The locations of the segment surfaces may be approximately symmetric about a perpendicular axis that is perpendicular to the segment region axis and intersects the segment region axis at the cylinder axis. The shortest distance A for each segment surface may be approximately equal for all segment surfaces.
In one aspect of the present invention, the covering cap may comprise four segment surfaces.
In another aspect of the present invention, the segment surfaces may be substantially flat or have a substantially cylindrical curvature.
In another aspect of the present invention, where the covering cap has a conical cylindrical shape, the segment surfaces may be conically inclined to a cap closure of the covering cap with respect to the cylinder axis.
In another aspect of the present invention, a difference (R2xe2x88x92R1) between the segment region inside radius R2 and the inner aperture radius R1 may be approximately equal to a wall thickness D of the covering cap. Further, a difference (R1xe2x88x92A) between the inner aperture radius R1 and said shortest distance A is approximately equal to the wall thickness D of the covering cap. The wall thickness of the covering cap may be approximately 1 mm.
In another aspect of the present invention, the segment regions may be marked on an outer surface of the covering cap by a ribbed surface structure configured to be gripped.
In another aspect of the present invention, the wall thickness D of the covering cap and a material composition of the covering cap may be coordinated with one another such that the covering cap can be deformed elastically.
In another aspect of the present invention, a circumferential angle between two adjacent segment surfaces may be smaller than a circumferential angle between a segment surface and an adjacent segment region.
In another aspect of the present invention, a circumferential segment region angle, which is the largest continuous angle that includes one segment region but does not include a segment surface, may be greater than a circumferential segment surface angle, which is the largest angle including only adjacent segment surfaces and the angle between them.
The present invention also provides for a cylindrical covering cap for an eyepiece tube, the eyepiece tube having a conical soft eyecup, comprising, in a cylindrical interior of the covering cap: two mutually opposite segment regions having a segment region inside radius that is greater than an inner aperture radius of the covering cap; and at least two mutually opposite segment surfaces that are circumferentially spaced so that the locations of the segment surfaces are approximately symmetric about a segment region axis that passes through a center of each of the segment regions, wherein a shortest distance from a segment surface to a cylinder axis passing through a center of the covering cap is smaller than the inner aperture radius of the covering cap, wherein the inner aperture radius of the covering cap is configured to adapt to a larger outside radius of the conical eyecup, wherein the locations of the segment surfaces are approximately symmetric about a perpendicular axis that is perpendicular to the segment region axis and intersects the segment region axis at the cylinder axis, wherein a circumferential angle between two adjacent segment surfaces is smaller than a circumferential angle between a segment surface and an adjacent segment region, and wherein a circumferential segment region angle, which is the largest continuous angle that includes one segment region but does not include a segment surface, is greater than a circumferential segment surface angle, which is the largest angle including only adjacent segment surfaces and the angle between them.